1. Field of the Invention
The present invention relates to a process for inserting rigid segments in a continuous web of paper, and more particularly, to such a process that requires the insertion to take place during the formation of the web of paper.
2. Description of the Related Art
A number of techniques have been used to code security paper, such as the paper used for legal tender bills and negotiable instruments in general that carry a nominal value superior to their intrinsic value. Most of these techniques involve the use of water marks and other impressions on the paper that attempt to make it unique in order to frustrate the efforts of wrongdoers that try to duplicate these techniques. The use of a rigid body, preferably with ferromagnetic characteristics in one of the contemplated applications of the present invention, inside the paper creates an unsurmountable burden for these wrongdoers, specially if the rigid segment can be uniquely coded.
The insertion of a rigid body in a paper web faces a number of problems. One of these problems is associated with the marked difference in coefficients or modulus of elasticity of the paper being formed and the rigid body being inserted. This is further complicated by the demands imposed by the current production processes of large quantities of security papers such as the one used for printing money bills, stocks, bonds, checks, etc., which require the precise alignment of these rigid segments in relatively large sheets for subsequent cutting and printing operations.